Chigger Bites · What Are They, Appearance, and More

Chiggers bites are bites from the larval form of the trombiculid mite, also known as chiggers. Other names for this mite include berry bugs, bush-mites, red bugs, and harvest mites. In general, chiggers live in low grasses, weeds, and shrubs in tropical, humid climates year-round. However, most bites occur during summer through early autumn, which coincides with their breeding season.  

 Chiggers tend to attach to and bite the exposed skin of an individual who spends time in their habitat. The bites will often be located in a cluster around areas of tight clothing, like the ankles, or along the waistline since the tight clothing restricts movement of mites. They are often found behind the knees, and between the toes as well. Upon attaching to the skin, the mites inject saliva that breaks down skin cells. The affected individual’s immune system then reacts to the chemical compounds in the mites’ saliva, resulting in the intense pruritus associated with chigger bites. In areas near Southeast Asia and Australia, chiggers may carry the bacteria Orientia tsutsugamushi, which can cause scrub typhus in infected humans. 

Chigger bites are usually diagnosed based on history of an intensely itchy rash that occurs 2-3 hours after spending times outdoors in grassy or wooded areas. Chigger bites can also be diagnosed on physical examination, revealing the characteristic 1-2 mm papules, commonly along the waistline, ankles, behind the knees, and around the toes.  

Occasionally, the diagnosis will be confirmed by removing any remaining mites via tape stripping, during which a piece of tape is firmly pressed to the skin and quickly removed, and then identifying the removed mites using light microscopy. 

Treatment of chigger bites involves removing any remaining chiggers and controlling the associated symptoms. Generally, taking a hot shower or a bath and cleaning the affected area with soap and water can help remove chiggers from the body. Applying an antiseptic solution such as hydrogen peroxide to the bites can kill any remaining chiggers on the skin. Since itching and inflammation often persist after the mites are gone, over-the-counter anti-itch creams, such as calamine lotion, and creams containing camphor and menthol can be used. Topical corticosteroids may be recommended to provide relief of itching, and oral antihistamines like cetirizine or hydroxyzine may also be taken to ease the inflammatory response. For intense itching, intralesional corticosteroid injections can be used to reduce swelling and relieve pruritus.